Carton clamps



Feb. 27, 1968 o. s. CARLISS ETAL 0 CARTON CLAMPS 5 Sheets-Shee Filed Sept. 29, 1965 ATTOP/Yf) 11 'IIHIIII INVENTORS 59 A. How-01v OSWALD 5. CARL/SS @74 54x14. ,IKL?

Feb. 27, 1968 O. S. CARLISS ETAL CARTON CLAMPS Fi:l.E.

3 Sheets-She Filed Sept. 29, 1965 INVENTORS 7 mi wmwm A A 1; m a

United States Patent 3,370,880 (IARTON CLAlWPS Oswald S. Carliss, Rydal, and Earl A. Horton, Philadelplain, Pa, assignors to Eaton Yale & Towne, 1112., a corporation of ()hio Filed Sept. 29, 1965, Ser. No. 491,324 Claims. (Ci. 24-87) ABSTRACT 6F THE DISQLGSURE A lift truck is equipped with a pair of arms mounted for load clamping movement, each arm comprising a yielding plate that supports a single clamping pad plate for engaging one side of a load such as a stack of cartons. The pad plate is substantially fiat but can fiex somewhat, and is mounted at points that are arranged in two vertical lines each at a distance that is approximately 22 /2% of the length of the pad plate from a vertical edge of that plate. The supporting arm plate is slotted to form an integral forward yielding portion on which is one of the vertical lines of mounting points for the clamping pad plate. Extending from that forward portion of the arm plate in a rearward direction are fingers on which is the outer line of mounting points for the pad plate. At each mounting point, the clamping pad plate is supported through a rubber pad, with vertically and horizontally arranged pairs of bolts engaging one pair the pad plate and another pair the supporting plate, permitting universal yielding of the pad plate as it flexes due to the clamping pressures.

This invention relates to load clamping attachments for industrial trucks, and more particularly to an improvement on the load clamp that is shown in the patent to George F. Quayle, No. 2,956,700.

In the Quayle patent, there is a clamp arm formed from a steel plate which is so cut as to contribute yielding fingers, and those fingers support a pair of clamping pads for engaging the load. When clamping the load relatively to an opposed clamp arm, each of those pads will yield independently on the fingers, tending to distribute the pressures that are applied to the load and making the clamp suitable for handling cartons.

The Quayle construction has met with considerable success. However, there are certain disadvantages in using more than one clampin pad on each clamp arm, and many of the users of load clamps do prefer that there merely be a single pad for engaging a particular side of the load. The novel clamp attachment that we contribute by our invention will have merely one clamping pad at each side, but nevertheless will operate extremely well when utilized for clamping a series of cartons.

Where the prior art has utilized single pads for clamping cartons, it has been thought necessary to design the pads with considerable curvature in order that they may operate properly. However, because of their curvature, the pads tend to concentrate the clamping pressures at certain points, sometimesdamaging the cartons. Through the concept of our invention, it is possible to utilize a single pad that is substantially flat, and that will effectively distribute the clamping pressures.

We have found by investigation that a single clamping pad will operate best if it is supported in a particular manner on the clamp arm, with securing means that are located at points which are 22 /2 of the length of the pad away from opposed front and rear edges of the pad. For example, if the clamping pad were to be 100 inches in length, each securing means would be arranged 22 /2 inches from the corresponding end of the pad.

3,37%,886 Patented Feb. 27, was

As a feature of our invention, we support a clamping pad through a series of securing means that can yield universally. Those securing means are arranged along vertical lines on the clamping pad, and will allow the pad to flex somewhat so as to apply effective clamping pressures to the load. As a more detailed feature, each securing means will include a yielding member, with horizontally and vertically arranged pairs of bolts that will firmly support the clamping pad while enabling the pad to move in both horizontal and vertical axes as the yielding member yields.

We have thus outlined rather broadly the more important features of our invention in order that the detailed description thereof that follows may be better understood, and in order that our contribution to the art may be better appreciated. There are, of course, additional features of our invention that will be described hereinafter and which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception on which our disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of our invention. It is important, therefore, that the claims be regarded as including such equivalent constructions as do not depart from the spirit and scope of our invention, in-order to prevent the appropriation of our invention by those skilled in the art.

In the drawings:

FIGURE 1 shows a side view of an industrial lift truck utilizing our novel clamping attachment.

FIGURE 2 shows a plan View of our novel clamping attachment, partly broken away.

FIGURE 3 is similar to FIGURE 2, but shows the position of the clamping attachment when clamping a series of cartons.

FIGURE 4 is a side view showing our attachment in more detail.

FIGURE 5 shows an exploded view of one clamp arm.

FIGURE 6 shows one of the yielding pad mountings.

FIGURE 7 shows a section on the line 77 in FIG- URE 4.

Referring now more particularly to FIGURE 1 of the drawings, we show our novel load clamping attachment 19 mounted on the lifting carriage 11 of an industrial lift truck T. The attachment 1% has two opposed clamp arms 12, 13, both of which may be seen in FIGURE 2, that are supported through clamp operating mechanism 14 on the lifting carriage 11. For purposes of disclosure, we show the operating mechanism 14 equipped with slide members is on which the clamp arms 11 and 12 are mounted, and hydraulic rams 16 for moving the arms and slide members. We believe that it will be unnecessary to go into further detail as to the clamp operating mechanism 14 because that mechanism may be conventional, and it is merely necessary here to know that the clamp arms 12, 13 move in a lateral direction relatively to each other for clamping a load between the arms.

In our invention, each of the clamp arms 12, 13 comprises an integral metal plate which is slotted as shown in FIGURES l, 4 and 5 so as to form fingers 17 that extend in a rearward direction from a forward end portion 18 on the plate. The slotting of the plate leaves connecting portions 19 between the forward portion 18 and a main part of the clamp arm, and a relatively wide base portion 17a on each finger 17. Further, each finger 17 is so bent that the end portion 17b of the finger extends at a small angle in an inward direction, or in other words, toward a load that may be in position between the clamp arms 12, 13. The finger end portions 17b and the plate end portion 13 form pad supporting portions on clamp arms 12, 13 as will be seen presently. The rearward end portion 20 of each arm is bolted to an angle member 21 that is welded 3 to the slide members 15, as indicated in FIGURE 4. We prefer to bend the rearward arm portions 20 slightly as shown in FIGURES 2, and 5, so that the arms 12, 13 normally will be supported at a small inward inclination or taper.

On each of the clamp arms 12, 13 of our invention, we utilize merely a single clamping pad 25. Each of those clamping pads 25 comprises a plate, of a material such as aluminum, which is sufliciently thin that it will have no great resistance to flexing when accepting the pressures that are incidental to clamping a load. When free from pressure, as in the position shown in FIGURE 2, the pad 25 will be fiat, or substantially so. Each clamping pad 25' is equipped with a facing 26 of friction material, which may very well be rubber, as is quite usual on pads that are utilized for clamping loads. Merely for convenience, we prefer to make the facing 26 in several sections, as indicated in FIGURES 4 and 5.

To secure each clamping pad 25 to its corresponding arm 12 or 13, we utilize a series of yielding mountings 27. Each mounting 27 will have a construction which is best seen in FIGURES 6 and 7, comprising a fiat member 28 of rubber or similar yielding material, and a pair of metal face plates 29 on opposed sides of the member 28.

Each of the face plates 29 has a pair of openings 30 that are formed to provide depressed'seats for bolt heads, and a pair of somewhat larger openings 31 so arranged as to lie in a line that is arranged at right angles to the pair of openings 35. The plates 29 are so assembled that the openings 39 of one plate are in aligned relation to the openings 31 of the other plate, there being corresponding through openings in the rubber member 28.

Referring to FIGURE 7, we secure each of the mountings 27 by a pair of bolts 32 that are inserted in one direction through the mounting and into threaded openings in a part of a clamp arm 12. Further, we insert a pair of bolts 33, one of which can be seen in FIGURE 7, in the opposed direction through the mounting 27 and into threaded openings in clamping pad 25. Bolts 32, 33 then act through the mounting 27 to secure clamping pad 25 to clamp arm 12, firmly supporting the pad on the arm. For reasons that will appear, we leave some clearance between the surface of the clamp pad 25 and the heads of bolts 32, and also between the arm 12 and the heads of bolts 33.

In order to explain the operation of the yielding mountings 27, it will be best to refer to FIGURE 4. We show each mounting 27 so arranged that its pair of bolts 32 are spaced longitudinally of the clamp arm 12, so as to lie substantially in a horizontal line. Also, bolts 33 are in a substantially vertical line and are arranged above and below the horizontal line. Thus, When the rubber member 28 of each mounting 27 yields, the clamping pad 25 can move about the horizontal axis of the pair of bolts 32 on the particular mounting, and also about the vertical axis of the pairtof bolts 33 In addition, the clearance of bolts 32, 33 will allow the clamping pad 25 to have some linear movement.

We further call attention to the fact that the yielding mountings 27 are arranged in two vertical lines, three of the mountings 27 being shown in FIGURE 4 on the forward end portion 18 of clamp arm 12, and two mountings 27 on the fingers 17. The vertical lines of the mountings 2'7 are arranged at points which are 22 /2 of the length of the clamping pad 25 from the opposed front and rear 'edges of the pad. Of course, there may be a slight variation in the percentage due to unavoidable tolerances in the manufacture and assembly of our attachment, and therefore we do not wish to be limited by the most extreme precision. In any event, however, the vertical lines of the mountings 27 will be located at a distance which is more than 22% and less than 23% the length of the clamping pad 25 from a vertical edge of the pad.

We have already mentioned the fact that the clamping pad 25 can flex. That flexing will be possible due to the particular operation of the yielding mountings 27, as we have described. Further, clamping pad 25 may flex whether or not the clamping pressures require that'the fingers 17 and end portion '18 yield relatively to one another on the clamp arm 12 or 13. Thereby, the clamping pad 25 will engage a load with substantially equal pressures distributed over a side of the load. Moreover, we have found that the pressures will be even better distributed when the yielding mountings 27 are positioned in the particular vertical lines that we have described.

Our novel clamping attachment will very effectively engage and hold a series of stacked cartons and will not cause concentrations of pressure that will tend to damage the cartons. We have found that our attachment will 0perat'e effectively even when handling loads that do not engage the full area of the clamping pad 25, as shown for example in FIGURE 3.

The clamp arm of our attachment actually is quite thin. Thus, as shown in FIGURE 3, the arm 12 together with its pad 25 will take up little room in a lateral direction, making it possible to handle'a load in a position that is closely juxtaposed to a wall or another loadFurther, the outer surface'of the arm is relatively smooth, so that the arm may more easily be inserted between loads for the purpose of forcing them apart preparatory to clamping one load.

We achieve all of these things while utilizing merely a single clamping pad for engaging each side of a full load. We believe, therefore, that the very considerable value of our novel clamping attachment will be understood, and that the merits of our invention will be fully appreciated by those persons who are skilled in the art.

We now claim: V

1. In a clamp attachment of the class described, a clamp arm having a series of pad supporting portions formed thereon, a clamp pad comprising a single plate secured to said pad supporting portions of the arm so as to be mounted in position on said arm for coacting with a load such as a series of stacked cartons, said single 'plate adapted to flex somewhat due to pressures between the plate and load, and said pad supporting portions being positioned on said arm for fastening to said plate along two lines with each line vertical and located at a distance which is more than 22% and less than 23% the length of the pad' from an edge of said pad that is vertical when said pad is held in a vertical plane.

2. In a clamp attachment of the class described, a

22% and less than 23% the length of the pad from an edge of said pad that is vertical when said pad is held in a vertical plane.

3. In a clamp attachment of the class described, a clamp arm having a series of pad supporting portions 7 formed thereon, a clamping pad comprising a single plate that is adapted to flex somewhat, securing means securing said single plate to each pad supporting portion of the arm so as to mount said plate in position for coacting with a load such as a series of stacked cartons, yielding means forming a part of each securing means and allowing universal movement of the single plate relatively to each pad supporting portion of the arm when said plate flexes, and said securing means being positioned along two 7 lines with each line vertical and located at a distance which is more than 22% and less than 23% the length of the pad from an edge of said pad that is vertical whe said pad is held in a vertical plane.

4. In a clamp attachment of the class described, a

clamp arm having a series of pad supporting portions formed thereon, a clamping pad comprising a single plate, securing means securing said plate to each pad supporting portion so as to mount said plate in a vertical plane for coacting with the side of a load such as a series of stacked cartons, each securing means comprising a pair of bolts spaced longitudinally of the clamp arm and lying in substantially a horizontal line, a pair of vertically spaced bolts lying in a substantially vertical line and positioned above and below said horizontal line, said bolts of each securing means being mounted one pair relatively to a pad supporting portion and one pair relatively to the plate, and said securing means being formed with clearance between said pairs of bolts and said plate and said pad supporting portions so as to allow said pad to move in substantially vertical and horizontal axes on each securing means relatively to said pad supporting portions.

5. In a clamp attachment of the class described, a clamp arm having a series of pad supporting portions formed thereon, a clamping pad comprising a single plate, securing means securing said plate to each pad supporting portion so as to mount said plate in a vertical plane coacting with the side of a load such as a series of stacked cartons, each securing means comprising yielding separating means between said supporting portions and said clamping pad, 2. pair of bolts spaced longitudinally of the clamp arm and lying in substantially a horizontal line, a pair of vertically spaced bolts lying in a substantially vertical line and positioned above and below said horizontal line, said bolts of each securing means being mounted one pair relatively to a pad supporting portion and one pair relatively to the plate, and said pad moving in substantially vertical and horizontal axes relatively to said pad supporting portions when said separating means yields on each securing means.

6. In a clamp attachment of the class described, a clamp arm having a series of pad supporting portions formed thereon, a clamping pad comprising a single plate that is adapted to flex somewhat, securing means securing said plate to each pad supporting portion so as to mount said plate in a vertical plane for coacting with the side of a load such as a series of stacked cartons, each securing means comprising yielding separating means between said supporting portions and said clamping pad, a pair of bolts spaced longitudinally of the clamp arm and lying in substantially a horizontal line, a pair of vertically spaced bolts lying in a substantially vertical line and positioned above and below said horizontal line, said bolts of each securing means being mounted one pair relatively to a pad supporting portion and one pair relatively to the plate, and said pad moving universally about said pairs of bolts on each pad supporting portion when said separating means yield and the single plate flexes due to pressures between the clamping pad and the load.

7. In a clamp attachment of the class described, a movable clamp arm formed from an integral plate and having a series of pad supporting portions formed thereon by the slotting and deformation of said plate, a clamping pad comprising a single substantially flat plate, securing means securing said substantially flat plate to each pad supporting portion so as to mount said substantially fiat plate in a vertical plane for coacting with the side of a load such as a series of stacked cartons, each securing means comprising a pair of bolts spaced longitudinally of the clamp arm and lying in substantially a horizontal line, a pair of vertically spaced bolts lying in a substantially vertical line with said vertically spaced bolts above and below said horizontal line, said bolts of each securing means mounted one pair relatively to a pad supporting portion and one pair relatively to the plate of said clamping pad, and yielding separating means between said sup- P ting p rtions and said clamping pad whereby said pad may move in substantially vertical and horizontal axes about said pairs of bolts on each securing means relativeiv to the pad supporting portions.

8. In a clamp attachment of the class described, a cramp arm, a clamping pad, means securing said clamping pad to said clamp arm comprising a pair of bolts spaced longitudinally of the clamp arm, yielding means through which said bolts connect said pad and arm, said bolts lying in a horizontal line, a further pair of bolts spaced above and below the first pair of bolts and also connecting the pad and arm through said yielding means, said further pair of bolts lying in a line that is intermediate the bolts of the first pair of bolts and that is vertical when the clamping pad is held in a vertical plane, and said yielding means enabling said clamping pad to rotate about each pair of bolts relatively to the clamp arm.

9. In a clamp attachment of the class described, a clamp arm comprising an integral plate which is slotted to form a series of pad supporting portions that are yieldable relatively to one another, a clamping pad comprising a substantially flat single plate that is adapted to flex somewhat, a series of securing means engaged between parts of said substantially flat plate and said pad supporting portions of the clamp arm and positioned along two lines located distances which are approximately 22 /2% the length of the pad from opposed edges of the pad, said lines being vertical when said pad is held in a vertical plane, said securing means mounting the clamping pad in position on said arm for coacting with a load such as a series of stacked cartons, a pair of vertically spaced bolts forming a part of each securing means and lying substantially in one of said vertical lines, a further pair of bolts lying in a substantially horizontal line and spaced one at each side of the line of the vertically spaced bolts on each securing means, said bolts of each securing means being mounted one pair relatively to a pad supporting portion and one pair relatively to the plate of said clamping pad, and yielding means separating the clamping pad and each pad supporting portion and yielding to enable the clamping pad to move in vertical and horizontal axes about the bolts of each securing means when the pad flexes and the pad supporting portions yield due to pressures between the pad and the load.

10. In a clamp attachment for a lift truck, a clamp arm mounted in a forwardly extending position on the truck and comprising a generally vertical plate having a rearward end portion secured to the truck, a medial portion of said plate slotted to form relatively narrow yielding plate parts, an integral forward end portion of the plate supported on said relatively narrow plate so as to yield relatively to the rearward plate portion, and fingers integral with said yielding forward portion and extending from that portion rearwardly in positions alternating with the relatively narrow parts of the plate that support the forward portion, a clamping pad for engaging a load and comprising a single plate juxtaposed to the rearward, medial and forward portions of the arm plate, and a series of securing means securing said single plate to said yielding forward portion of the arm plate and to said fingers at points that are arranged along two vertical lines spaced considerable distances from opposed front and rear edges of said single plate of the clamping pad.

References Cited UNITED STATES PATENTS 3,145,866 8/1964 Farmer 294-67 GERALD M. FORLENZA, Primary Examiner, G. F, ABRAHAM, Assistant Examiner. 

